VR head-mounted display lens distortion can maximize covering of the warping of a visual range of a person, to present a larger field of view and enhance sense of immersion of experience. When an image on a display screen is amplified by using a lens, the image is distorted. To cancel the distortion, the image needs to be stretched and warped. In this way, an undistorted image is projected to the eye's retina. The technology is referred to as anti-distortion.
A rainbow is formed when a white light is made to pass through a prism. That is because different colors have different light refractive indexes. A same scenario occurs at the edge of a VR lens. To resolve the problem, a practice similar to anti-distortion is used. According to a principle of optical path reversibility, anti-dispersion is first performed before an image enters the lens. In this way, the image through the lens is normal. The technology is referred to as anti-dispersion.
Asynchronous time warping (ATW) is a technology for generating an intermediate frame. When a game or video image cannot keep a sufficient frame rate, the ATW can generate the intermediate frame, thereby effectively reducing video jitter of the image. When a VR device is used, head moves excessively quickly, resulting in delay of scenario rendering. The time warping warps, based on a direction, an image before being sent to a display, to resolve the delay problem. The ATW technology is widely applied to VR products and the like, effectively overcoming image jitter and delay, thereby reducing sense of dizziness.
Most of existing implementations are anti-distortion, anti-dispersion, and asynchronous time shift that are based on GPU acceleration, typically including a Gear VR product, an oculus VR head-mounted display product, and a cardboard head-mounted display product. All the products pose a challenge to GPU performance, DDR speed, display latency, and overall power consumption. The prior art mainly has the following defects: the anti-distortion, the anti-dispersion, and the ATW are performed in steps by using GPU or through software operation; anti-distortion, anti-dispersion, ATW calculation need to cost GPU load and system load; ATW requires GPU hardware to support a proper preemption granularity, and requires an operating system and a driver program to support GPU preemption; during implementation, GPU processing is in memory-memory mode, consuming much bandwidth, and resulting in increased power consumption; and the GPU uses an offline mode, additionally increasing the processing delay and making VR experience worse.